Method and arrangement for producing nondamped oscillations



Feb. 19 1924. v v, 1,484,269

E.'MAYER METHOD AND ARRANGEMENT FOR PRODUCING NONDAMPED OSC ILLATIONS Fil ed Jufia' 21 1923 Fatented Feb. i9, 192%.

tantra EILEIL MAYER, OF CHARLOTTENBURG, GERIVI ANY.

ates

METHOD Ann naaanennrnnrroe raon'oornotonnaitrnn os'oiLLATIons. 7

Application filed June 21, 1923. Serial No. 646,958.

I do hereby declare the following to be a full, clear, and exact description of the invention, of which the following is a specification.

My invention relates to a method and arrangenient or combination for producing undamped electrical oscillations; especially oscillations of a frequency suitable for radio work. An object of the invention is to provide convenient means whereby I can charge a circuit and then cause the circuit to discharge in a manner that will produce oscillations of the desired character. The charg-- ing of the circuit proceeds until the electrical energy stored in said circuit is such,

that when oscillations begin, the momentary value or strength of the oscillation current is substantially equal and opposite with respect to the value of the charging current, 3 and the circuit then oscillates under such conditions that the charging current will be substantially equal to the amplitude of the oscillation current still existing after one complete oscillation. The circuit can then be broken without sparking, and, after a tion embodies; and I, or" course, reserve-the right to make any'changes in the shape, size and arrangement of the various parts, or steps herein disclosed, within the nature and scope of the invention, as I have de-- fined the same in the appended claims.

In the drawing, Fig. 1 shows a circuitfor producing oscillations in accordance with my invention.

Fig. 2 1s a diagram to show the nature of the current employed iii-charging thecircuit by which the oscillations are produced. 7 Fig. 3 is a chart to show the oscillating current in its relation to the charging current. Figs. 4, 5 and 6 are views presenting different forms of circuit closers and in-,

Referring first to Fig. 1, I show. a charg ing circuit a and an oscillation circuit 6,. The charging circuit a will be connected to a source of direct current through a'pair of leads or conductors, in whichare' inductances D and resistances R; and the two leads will be connected by a conductor e, in which is a make-and-break -device, circuit closer, or interrupter'll. The circuit b is in parallel with the circuit a, being connected to they two terminals of the conductorc, and containing a condenser C, and inductances L. When the circuit through 0 is broken at the circuit closer or interrupter U, the direct current flowing in the circuit a will charge the circuit 6 and when the circuit through the conductor 0 is established, the condenser C will discharge through the circuit 6 and produce oscillations in thiscircuit. The number of interruptions of the circuit produced by the interrupter U will, of course, agree with the natural frequency of the circuit 6. If the circuit 6 were omitted, the energy in the circuit a during the time when the breaker U is closed, could berepresented by the diagramin' Fig. i 2, where values above the horizontal line. OX can be taken as indicating voltages and values plotted horizontally to the right of the vertical line OY can be taken as indicate in g currents. v

By referring to Fig. 3, one can see'inr detail the manner in which my method of producing undamped oscillation is accomplished. In this view, the broken line c above the horizontal line OX represents the direct current in the circuits a and b, the. full curved lined indicates the oscillating current in the circuit Z) and the dot-anddash line f represents the resultant current in the conductor 0, during the period when the circuit is completed through the con ductor 0, and oscillations are occurring. In considering this view, the distances above. the line OX may be taken as showing values of current, and the distances along the line OX to the right of the line OY, may be taken as representing time. Thus the distance O'A may be taken as the time during which the interrupter U opens the circuit through the conductor '0, so that the direct current in the circuit a flows into the circuit b and charges the condenser (3. During this period no oscillations take place.

While the charging of the condenser C continues,'the direct current will, of course, fall of)? somewhat as the charge 01 the condenser increases. This e-llect is represented in Fig. .3 by the curve e sloping downward in Fig. 3; from thepoint 3 in the line OY to the point g in the line A r Immediately at the end of the period represented by the distance 0A, the circuit closer U closes the circuit through the conductor 0, thecharging of the condenser nowha-ving proceeded to such a point that, when oscillations begin, the momentary value of the oscillating cur rent will be equal to the value of LllGdlIGCl) current at the pointy The establishment of the circuit through the conductor we means in effect the cutting down oftheresistance across the circuit-breaker U to zero, and vthis condition is maintained durr ing the time represented by the distance between the points A and B in Fig. 3. The oscillation current in the circuit 1) flowing through the conductor 0 and represented by the line d, then passes from practically itg maximuln value through zero and back to a point a little above itS original value, represented by the point g on the line 133 and the resultant current through the conductor ,0 is unidirectional as indicated by the. curved dot and dash line that is to say, the part of the curve d, w iich is below the line OX, will be added to the corresponding instantaneous Values of the direct or' charging current represented by the line above the line OX, now flowing through the conductor 0, and the values of the current iven by points in the line (5 above the line. ,X, willbesubtracted iroin the curve 6; whereby will be apparent that at the moment when the oscillations commence, the current through 0 will be zero and the moment when the circuit through c is again interrupted, the resultant current will have again been reduced to zero. At the time when the circuit through c is broken by the interrupter U, the value of the direct current will be equal and opposite to the monientary value of the oscillating current, an'd'theresistance of the circuit'c, will be practically infinitef Hence, when the circult is interrupted, no sparking will take place. While the circuit is interrupted, the direct current in the circuit a again charges the condenser Cover the period represented by the distance between the points B and A in the Fig. 3. The values By and A"y are the same as the values OY and fig respectively for the current curve e. Thus, by successive closings of the circuit through conductor 0, and successive interruptions, practically continuous oscillations of constant amplitude can be obtained; the periods or": interruption being relatively much shorter than the periods during which the oscillations take place. In connection with the principle of operation, one must bear in mind the fact that during the period when the interrupter U opens the circuit through the conductor 0, this conductor is free from current and the direct current now flows into the condenser C. When the interrupter U closes its circuit through the conductor a, the two circuits (6, and Z) are connected together through this conductor c and then the circuit a is a periodic circuit containing an E. M. .F., while the other circuit 6 is a normal oscillating circuit, without an E. M. F. When the interruption is effected in the conductor 0, the value of the oscillating current must be substantially equal and oppositein its intensity and direction tothe value of the direct current at the same instant, so thatinterruption can be effected in a sparkless manner, and charging must then beallowed to continue to such a point that when oscillations again commence, the oscillatingcun rent at the moment when it begins is just about equal to the value of the direct current.

To produce the making and the breaking of the circuit through the conductor 0, the interrupter U may have the structure shown in Fig. In this View the numeral 1 indicates fixed brush, and the numeral 2 an ad justable brush, which rub upon the surface of a cylindrical member consisting of conductor bars, or se ments 3, separated by insulation 4, the diametrically opposite bars 3, being connected in pairs by conductors 5. In Fig. 4, only a few of the conductors 5 are illustrated as running entirely across from one bar 3 to a bar diametrically opposite, to avoid showing too many lines at the center of this figure, but it is to be understood that all the lines 5 are continuous from a segment 3 at one extremity to a point 180 away measured around the circumference of tl e circuit closer. By adjusting the brush 2, the period during which the circuit is broken between the brushes 1 and 2 and the time when the circuit is made, can be so adjusted as to give the results which are in dicated in Fig. 3. Fig. 5 also shows a form of circuit closer with the brushes 1 and 2 rel atively close together, and each bar 3 is conmated by a conductor 5,;not to a bar 3 diametrically opposite, but to one .that is near er and the lines-5, although only a few are shown, will be equal in number to half the bars, so that they can connect these bars in pairs, the bars of each pair being the required distance apart, all around the circumference of the circuit closer; whereby each pair of bars and its associated conductor 5 can complete the circuit successively through the brushes 1 and 2. Ofcourse, the extremities of the conductor 0 will be connected to these brushes,

When two brushes are employed, the frequency depends upon the number of bars or conducting elements 3 and the number of revolutions of the circuit closer. With the same number of bars 3 and the same speed of rotation, the frequency can be doubled, treb-led or even further increased by providing 2, 3 or more sets of brushes in series. For instance, Fig. 6 shows brushes 1 and 2 co-operating with brushes 6 and 7 which are united by a continuous conductor 8. The brush 1 is shown as running upon the segment Z from which it will pass to the bar 177, and the brush 7 just leaving the bar n to pass over upon the bar 0. Similarly, brush 6 is in contact with a point adjacent the middle of the bar p, while the brush 2 is leaving the bar 9 to pass over on the bar 9". The bars Z and p are connected together and so are the bars'o and 2', six segments apart, so all around the circuit closer. Hence with the parts in the position shown, an interruption of the circuit through the conductor 0 is just occurring, because the circuit runs from the brush 1, to brush 6, then to brush 7 segment n and segment 9, to brush 2. When the brushes 7 and 2 reach the middle of the segments 0 and r, the brushes 1 and 6 will be passing ofi the segments Z and p respectively to the next segments. Hence, the two interrup tions are given in the circuit of the conductor 0, for each air of segments 3, owing to the resence of t e two additional brushes 6 and brushes co-operate, so that twice as many interruptions per revolution are obtained with the construction shown in Fig. 6, as, for example, with that shown in Fig. 4.

Mechanically the number of oscillations attainable with the process depends upon the exactness of the construction of the commutator and-of its brush device as well as upon the permissible speed or upon the degree of exactness with which the interrupters are working. If it is for instance assumed that the commutator has a permissible circumferential speed of 50 meters a sec 0nd and the number of periods of the high frequency oscillation which it is intended to produce amounts to 5000, then for every completed period 10 mm. are available at and the manner in which the four" adjusting the point of the circumference of, the commutator. Of these 10 mm. about 8 mm. are used for the 'closing period and 2 mm. for the opening period. The sparkless working of the commutatormakes it necessary in this case that the interrupting path be kept constant for the length of about 1 mm. which can be effected without difficulty. If with the same arrangement and the same circumferential speed 50000'periods .shallbe produced, the accuracy has to be increased to 1/20 mm. If in doing so, difficulties should arise, they 7 can be easily overcome if there is a replenish- -ing of the oscillation circuit with energy fromthe direct current source with every second, third period, etc. Then oscillations are obtained as illustrated'in Fig. 7.

This view shows oscillations consisting of produced by the interrupter can also be increased in the same manner as in static frequency transformers, in order to obtain the higher harmonics of the oscillations.

Having described my invention what I States 1s:--

l. lhe method of operating an apparatus for the production of continuous oscillations of the type in which a charging circuit is connected to an oscillatory circuit and is periodically short-circuited by an interrupter, said method comprising the adjustment of the point of short-circuit to occur at the instant when the current in the charging circuit becomes equal to and in the opposite direction to the initial value of the oscillatory current, with respect to the short-circuit through the interrupter, and the interruption of the short-circuit to occur protect by Letters Patent of the United at the instant when ice believe to be new and desire to secure and theoscillatory current through the intervrupter becomes equal and opposite to the current from the charging circuit.

operating an apparatus 2. The method of for the production of continuous oscillations of the type in which the charging circuit is connected with an oscillatory circuit and is periodically short-circuited by an interrupter, said method comprising the adjustment of the point of short-circuit to occur at the instant when the charging current becomesequal to and in the opposite direction to the initial value of the oscillatory current, with respect to the circuit through the interrupter. I

3. The method of operating anapparatus for the production 01" continueus oscillations of the type in which the charging circuit is connected with an oscillatory circuit and is periodically short-circuited by an inter rupter, said inethodcoinprising the adjustment of he point of the interruption of the short-circuit to occur at the instant when the oscillatory current in the interrupter becomes equal and opposite to the current from the charging circuit.

e. The combination of a charging circuit,

a circuit to receive energy from the charging circuit and produce oscillations, a conductor common to said circuits, a rotatable circuit-closer in the line of said conductor, said circuit-closer comprising conducting segments connected'in of said conductor .and running upon said segments, a second pair of brushes-between the first pair and connected together, said brushes being disposed at vsuch points and located at such Zdistances apart, that the circuit through the conductor can be interrupted and losed a plurality" of times for each pair of connected segments during each revolution. 7 v r In testimony whereof I have signed my name to this specification in the presence of two subscribing itnesses.

, E. M Y R;

Witnesses:

,E WINC. KURWEIDEL, Bureau '1. ANPA H.

pairs and separated by ins 'lation; a pair of brushes in the line 

